It's best to look at form before you look at colors. You have to build a house before you can paint it.

Find out what the faults are in your male and choose a female who will complement those faults and hopefully give you a better chance at fry without those faults.

If you want that specific coloration your best bet is to get a female with the same coloration, keep in mind however that if you don't know the genetics of the parents there's no way to know for sure the genetics of the fry. However, dark bodied bi-color seems to breed fairly true in the spawns I've seen with that coloration.

the trick with genetics is that with most pairings the offspring will have a combination of 2 chromosomes out of the 4 (usually) the parents provide xx (mom) and xy (dad). Since all offspring will have at least one x, and mom donates 2/3 of them, i'm not an expert at explaining it, it's been a while... but somehow you end up with 75% of offspring genetics being from the mother, outside of when dominant genes are involved, and there will always be some drift & blending in between.

When your chasing a particular trait (like his color), best to find a female that closely matches that color, possibly a sibling. If the sibling route is not possible, you find a female that just matches as close as you can, breed, and then eventually breed your male again with a female that resulted from the first pairing that displays the most of the trait you're after. And then that step may need to be repeated, matching siblings, offspring and parents until you reach a homozygous state where all the offspring display the traits you're after.

That's alot to take in i know, but the big thing to take away from most of this is that the female carries most of the genetics.

the trick with genetics is that with most pairings the offspring will have a combination of 2 chromosomes out of the 4 (usually) the parents provide xx (mom) and xy (dad). Since all offspring will have at least one x, and mom donates 2/3 of them, i'm not an expert at explaining it, it's been a while... but somehow you end up with 75% of offspring genetics being from the mother, outside of when dominant genes are involved, and there will always be some drift & blending in between.

I fully admit I'm no expert and am just getting into this hobby, but from what I've read, the diploid number for Betta splendans is 2n = 42. So, they each have 21 chromosomes arranged in pairs, and get half from the female parent and half from the male. Either parent can carry a dominant allele for any given trait. Maybe in special cases something different or weird can happen, but if I have the wrong general idea here, please let me know.

No you're mostly right, but of the 50% inherited from each parent, 49% of that is common to both parents (at least in people, i suspect fish it's a slightly lower %). That brings us to the sexing chromasomes... The X and the Y. Again both parents carry an X, but the female carries two of them to the male's one. So 2/3 of that last percent would be from the mother except that the Y is 2.5 times smaller than the X.

However, the Y chromasome remains virtually unchanged generation after generation, so long-term genetic changes are attached to the father DNA.

So for most things like color and finnage would rely mostly on the mother. And body size, shape, and probably ray counts would be from the father.

Of course other than the DNA amounts the rest of that is mostly theory.

Of course dominant genes trump all, and there's always mutation and genetic drift to stir things up once you think you figured it out.

Theoretical genetics and bettas are 2 different things.... lol
Theoretically the pair should contribute 50 - 50. But facts show that females are more dominant, at least for form.

But then again it all depends on their genetic background. We can't predict for certain what an outcome will be unless we know their background (about 3 generations) - who's genes are stronger (do they breed true or were they a result of blending) ..... I've been doing this for ages, yet they still surprise me. Lol ..... That's what makes breeding so interesting.

But the part about around 75% of the uncommon genetic material being supplied by the mother is factual, at least in most animals. Again, a dominant gene will take over like long fins, but even if the father is homozygus, only 50% would show that dominant trait, making you think that he supplied 50% of all, when it was simply that one gene.

But the part about around 75% of the uncommon genetic material being supplied by the mother is factual, at least in most animals. Again, a dominant gene will take over like long fins, but even if the father is homozygus, only 50% would show that dominant trait, making you think that he supplied 50% of all, when it was simply that one gene.

But bettas do have alot of recessive genes floating around due to all the random breeding for hundreds of years that make all kinds of random stuff pop up like you said.

My dear friend, I'm afraid you have no idea what you are talking about.

The information you provide about the size difference between the X and Y chromosomes is based entirely on humans. It doesn't hold true for all mammals, much less all fish. Some species of fish can have YY males, or XY females, or no X or Y chromosomes at all, to determine sex.

Alot of your other comments are just wrong. For example, whether breeding is "random" or "intentional" tells you absolutely nothing about the percentage of dominant or recessive alleles in a population.

Based on the research I was able to do this aft, I have learned that no one knows whether Bettas have XY chromosomes responsible for sex determination. One source said yes, two others (one a Yale professor) said no. The source that said "yes" also said the X and Y chromosomes in Bettas are the same size.

Even if Bettas had a big X chromosome and an tiny Y, I am highly skeptical that the genes coding for all of the traits you mention would fall on the X, and not on the other chromosomes.

I do think it is really interesting that breeders observe spawns tend to follow the female parent's traits. It would be really cool to understand the mechanisms for that one day, once the research has been done. Until then, we'll have to be content that we don't know.

In case you are interested, below are some of the links I was looking at.